These are not the first glow-in-the-dark rabbits: In 2000, artist Eduardo Kac commissioned a French lab to create for him a luminescent rabbit, Alba, also using borrowed genes from jellyfish. He called that rabbit art. The scientists called it science. A philosophical tussle ensued. And then a legal one. The glowing rabbit died before the matter was settled.

Since then, engineering animals to glow – cats, dogs, fish, sheep, pigs, and monkeys have all been made to do so – has been less an artistic endeavor, and more a burgeoning frontier in genetic research. Scientists say that the glow is tangible evidence that one animal can be made to accept and use the genes of another. And that, they say, is a sign that it might be possible to use similar advanced techniques to treat genetic diseases.

To make a glow-in-the dark bunny, the genes that give a jellyfish its glow in the dark are injected into a rabbit embryo. When those embryos are implanted in a mother rabbit, the bunnies that are born will have a single jellyfish trait: they will glow in the dark.

In this case, the genes were implanted into eight embryos. In two of them, the genetic modification took, making them glow.

But the bunnies don’t glow all the time. In daylight, the bunnies (which the researchers say are perfectly healthy) look typical: white, with compact little bodies. But, under ultraviolet light, the modified bunnies glow a Frankenstein green as they nuzzle each other, push around newspaper cuttings, and do other normal bunny things.